This invention is generally applicable to the recovery of uranium from aqueous HF solutions containing the same. It is based on our finding that intimately contacting such solutions with particulate CaF.sub.2 and then sedimenting the particulates effects removal of much of the uranium. That is, uranium is carried down out of solution by the sedimented CaF.sub.2 particles. The resulting solution then is separated from the sedimented, uranium-bearing particulates by any suitable technique. The mechanism by which the uranium is carried down is not yet well understood.
So far as is known, this process has not been reported previously. It is clear from the very low solutility of CaF.sub.2 in aqueous solutions that the well-known common-ion effect is not involved here. If the uranium is in solution as UF.sub.4 and no ionization has occurred, then the solubility-product principle would not be governing the carry-down of uranium. If the uranium is present as UO.sub.2 F.sub.2, the solubility of this species is too high to account for the carry-down of uranium when present in trace quantities.